Study On Working Characteristic And Mechanism Of Triggered Vacuum Switch

Triggered vacuum switch (TVS),as a high-power controlled-switch, has some advantages of compact construction, excellent performance, lower cost, quietness, high reliability, adaptability to environment and so on. TVS gets more and more attention in high power pulse technology applications and becomes an important control device in pulse power technology. And it expects TVS has future performance.This article is based on the work mechanism of TVS, the characteristics of TVS three stages are studied by experiments, which are triggering stage, switching stage and dielectric recovery stage. And it focuses on the characteristics of triggering delay time and trigger resistance; switching delay time; vacuum arc and dielectric recovery characteristics under high-frequency high-current conditions.First of all paper, on the TVS structure and working mechanism, the triggering delay time and its jitter, trigger resistance characteristics are studied by experiments. Triggering delay time is influenced not only by the materials and structural of electrode, but also by the amplitude of main gap voltage and the polarity of main gap voltage and triggering voltage polarity. It is found that, Polarities of the main gap voltage and the trigger pulse strongly influence the triggering time delay characteristics of TVS. TVS has high working stability in the operation mode applying a positive voltage to the main gap and it has a range of stably working voltage. Too low or too high voltage across the main gap is inconvenient for successful triggering. In the range of stably working voltage, the influence of the main gap voltage magnitude on triggering delay time is not prominent. It is also found that, as the trigger energy increases, triggering time delay and the jitter decrease. Trigger resistance affects the life of TVS, and is affected by the trigger current and the arc. It is found that the action of the arc is far greater than that of the trigger current. After several experiments, it has the trends that the trigger resistance increases, triggering voltage decreases. And it is proposed that the impact of vapor deposition should be controlled, to improve product life and stability of their work performanceThe characteristics of switching delay time and its jitter, vacuum arc under high-frequency high-current conditions are also studied by experiments. Switching time delay is affected by polarity of trigger voltage and trigger energy. TVS has high working stability in the operation mode applying a positive voltage to the main gap and as the trigger energy increases, switching time delay and its jitter decrease. Under the high-frequency and large-current, TVS has the positive volt - ampere characteristics. With the arc current increasing, the arc voltage increases significantly. TVS arc will appear as three arc shape: diffused arc, gathering arc and transition arc. The arc voltage of diffusion arc is lower, and is superimposed on a slight high-frequency noise voltage signal. In the transition process, arc voltage increases dramatically, and is superimposed on a high frequency voltage components. It is caused by appearance and disappear of the anode spots produce and disappear. The more unstable of anode spots, the more noise component superimposed on the arc voltage.And it is also found that, dielectric recovery characteristics under high-frequency high-current conditions are affected not only by the peak current and current rate of change, but also by frequency and rise of recovery voltage. As the frequency increases, the breaking capacity of TVS decreased. When frequent is lower, less than 2500Hz, as the frequent increases, the breaking capacity decreases significant. But when frequency is more than2500Hz, the decreasing trend is not significant. As frequency increases, the peak of breaking current trends to decrease but the current rate of change trends to increase. The breaking capacity of TVS under high-frequency is decreased as the recovery voltage increases.